diff --git a/src/Resolvers/UserAgentResolver.php b/src/Resolvers/UserAgentResolver.php
index 3a0b93f5..6a714a14 100644
--- a/src/Resolvers/UserAgentResolver.php
+++ b/src/Resolvers/UserAgentResolver.php
@@ -10,6 +10,6 @@ class UserAgentResolver implements Resolver
 {
     public static function resolve(Auditable $auditable): string
     {
-        return $auditable->preloadedResolverData['user_agent'] ?? Request::header('User-Agent');
+        return $auditable->preloadedResolverData['user_agent'] ?? Request::header('User-Agent', '');
     }
 }